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Lipids

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Lipids

  1. 1. Lipids Fats and Oils Steroids Phospholipids 03/09/10
  2. 2. Lipids <ul><li>Nonpolar - mostly C, H – like hydrocarbons </li></ul><ul><ul><li>Hydrophobic – don’t dissolve in water </li></ul></ul><ul><ul><li>Feel slippery/oily </li></ul></ul><ul><li>Some fatty acids are ESSENTIAL 1 </li></ul>03/09/10
  3. 3. Fats and Oils are Triglycerides: They are built out of glycerol and fatty acids <ul><li> </li></ul><ul><li>glycerol </li></ul><ul><li>fatty acid (note hydrocarbon chain </li></ul><ul><li>and functional group –COOH </li></ul><ul><li>= carboxyl or acid group) </li></ul>03/09/10
  4. 4. A Monoglyceride Forms <ul><li>glycerol + 1 fatty acid  monoglyceride + water </li></ul><ul><li>What type of chemical reaction? </li></ul><ul><li>Dehydration synthesis </li></ul>03/09/10
  5. 5. A Triglyceride Forms 03/09/10
  6. 6. Triglycerides Types of Fatty Acids <ul><li>Fatty acid one is? </li></ul><ul><li>Saturated </li></ul><ul><li>Fatty acids 2 and 3 are? </li></ul><ul><li>Unsaturated </li></ul>03/09/10
  7. 7. Triglycerides MUFAs and PUFAs <ul><li>Fatty acid 2 is? </li></ul><ul><li>Monounsaturated (MUFA) </li></ul><ul><li>Fatty acid 3 is? </li></ul><ul><li>Polyunsaturated (PUFA) </li></ul>03/09/10
  8. 8. Trans-Fats are Unhealthy 03/09/10 <ul><li>Trans-fats form when unsaturated fats are partially hydrogenated </li></ul><ul><li>They are found in many processed foods </li></ul><ul><li>They should be avoided </li></ul>
  9. 9. Saturated vs. Unsaturated <ul><li>More dense, harder </li></ul><ul><ul><li>Butter, tallow, palm & coconut oil, e.g. </li></ul></ul><ul><li>More liquid, less dense </li></ul><ul><ul><li>Canola, flax, fish oils, e.g. </li></ul></ul>03/09/10
  10. 10. Essential Fatty Acids… <ul><li>… are always polyunsaturated </li></ul><ul><li>… are linoleic and linolenic acid </li></ul><ul><li>… were first found in lin (= flax ) seed oil </li></ul><ul><li>Flax or lin is the plant that supplies us with the fibers for linen </li></ul><ul><li>Flax – The Blue Flower of Romanticism </li></ul>03/09/10
  11. 11. Essential Fatty Acids <ul><li>polyunsaturated </li></ul><ul><li>found in: </li></ul><ul><ul><li>plant oils (especially flax seed (lin), canola, soy </li></ul></ul><ul><ul><li>fish oils </li></ul></ul>03/09/10
  12. 12. Fatty Acid Composition of Oils and Fats 03/09/10
  13. 13. Lipids Function In Living Things 03/09/10
  14. 14. Function of Lipids <ul><li>Energy storage, insulation, shock absorption </li></ul><ul><ul><li>fats, oils </li></ul></ul><ul><li>Protection </li></ul><ul><ul><li>oils, waxes </li></ul></ul><ul><li>Component of cell membranes </li></ul><ul><ul><li>phospholipids, cholesterol </li></ul></ul><ul><li>Hormones </li></ul><ul><ul><li>sex hormones </li></ul></ul><ul><ul><li>other steroid hormones </li></ul></ul><ul><li>Carriers </li></ul><ul><ul><li>for fat-soluble vitamins </li></ul></ul><ul><li>Provide Flavor </li></ul><ul><ul><li>to foods </li></ul></ul>03/09/10
  15. 15. Function of Lipids – Energy Storage and Insulation <ul><li>Energy storage </li></ul><ul><li>Insulation </li></ul>03/09/10
  16. 16. Function of Lipids – Shock Absorption <ul><li>Shock absorption </li></ul><ul><ul><li>Fat cushions inner organs like kidneys </li></ul></ul><ul><li>When body fat gets too low, they are at risk </li></ul>03/09/10
  17. 17. Waxes For Building and Coating <ul><li>Bee hive </li></ul><ul><li>They also coat (shiny) leaves, to prevent evaporation </li></ul>03/09/10
  18. 18. Cell Membranes Fatty acids are used to make: Phospholipids and Cholesterol 03/09/10
  19. 19. Phospholipids Build Cell Membranes <ul><li>Phospholipids build them </li></ul><ul><li>Cholesterol stabilizes </li></ul>03/09/10
  20. 20. Phospholipids <ul><li>Depending on the fatty acids in the phospholipids, cell membranes will have different properties (fluidity e.g.) </li></ul>03/09/10
  21. 21. Phospholipids form Membrane Bilayers 03/09/10
  22. 22. Cell Membrane 03/09/10
  23. 23. All cell membranes in all cells and around all cell organelles are made from phospholipids 03/09/10
  24. 24. Sidebar: Liposomes <ul><li>Sources: </li></ul><ul><li>www.happi.com/special/ jan011.htm </li></ul><ul><li>www.gilead.com/wt/tert/ liposome_tech </li></ul>03/09/10 Liposomes are spherical envelopes created by mixing phospholipids and cholesterol. Liposomes can be used for targeted delivery of drugs and cosmetics to cells
  25. 25. Carriers for Fat-Soluble Vitamins <ul><li>Fat-soluble vitamins (A, D, E, K) can only be absorbed when consumed with fats/oils. </li></ul><ul><li>These vitamins from salads are significantly better absorbed when the dressing contains oil. </li></ul><ul><ul><li>Salad dressings can contain the fats we need, in their best form: raw </li></ul></ul><ul><ul><li>Conclusion: Fat-free dressings are a stupid invention </li></ul></ul><ul><ul><li>If you are getting too many calories it is better to cut calories elsewhere. </li></ul></ul>03/09/10
  26. 26. Which is the fattiest organ of your body? Your brain! 03/09/10
  27. 27. The Brain Is Your Fattiest Organ <ul><li>It is ~60% fat </li></ul><ul><li>DHA (ω 3) = 1/3 of the brain’s gray matter (that’s what you think with), needed for: </li></ul><ul><ul><li>nervous system </li></ul></ul><ul><ul><li>retina ( eyes) </li></ul></ul><ul><li>DHA links: plant oils , fish oil, </li></ul>03/09/10 Fatty membrane layers (phospholipids), long, flat cells wrapped around axon Neurons – nerve cells
  28. 28. Essential Fatty Acids <ul><li>Many preemies, fed on formula, ended up with visual problems, until we discovered this: </li></ul><ul><li>DHA (docosahexaenoic acid - ω 3) and </li></ul><ul><li>ARA (arachidonic acid - ω 6) are essential fatty acids necessary for proper brain and eye development of 3 rd trimester infants </li></ul>03/09/10 See also : Formula Additives Boost Small Children's Intelligence In Study
  29. 29. Lipid Hormones Sex and other hormones 03/09/10
  30. 30. Sex Hormones are Lipids <ul><li>50+ steroid hormones are made from cholesterol </li></ul><ul><li>Not all are </li></ul><ul><li>sex hormones </li></ul>03/09/10
  31. 31. “ Male” and “Female” Sex Hormones 03/09/10
  32. 32. Hormone Production Pathways <ul><li>“ In the body, testosterone and some other steroids are made from cholesterol (not always a bad guy) through a sequence of chemical reactions. </li></ul><ul><li>The chemical names next to the arrows are enzymes that catalyze the indicated reaction. </li></ul><ul><li>Note that testosterone is produced from one female hormone (progesterone) and is the precursor to another (estradiol).” </li></ul>
  33. 33. Sex Hormones <ul><li>Fat cells produce the enzyme aromatase, which converts testosterone to estrogen: </li></ul><ul><li>testosterone aromatase  estrogen </li></ul><ul><li>This may have a feminizing effect on fat men. </li></ul><ul><li>Some of these men actually grow breasts that produce milk. </li></ul>03/09/10
  34. 34. Cholesterol  Vitamin D <ul><li>With enough sun exposure, vitamin D becomes non-essential </li></ul>03/09/10 in skin cells UV
  35. 35. Sidebar: Bone Density <ul><li>50% out of 100,000 women with hip fractures due to osteoporosis never get back on their feet </li></ul>03/09/10
  36. 36. Osteoporosis 03/09/10 Source and more info: http://www.mrc-hnr.cam.ac.uk/research/bone_health/bone_health.html
  37. 37. When is the Best Time to Increase Peak Bone Mass? 03/09/10 ____________ risk zone See which sport enhances bone density in which part of the body: This is a great site on bone health
  38. 38. Factors in Bone Density <ul><li>Nutritional </li></ul><ul><li>calcium (take Ca: Mg in 2:1 ratio) </li></ul><ul><li>vitamin D (sun exposure) </li></ul><ul><li>vitamin K 2 ( menaquinone ) </li></ul><ul><li>vitamin C </li></ul><ul><li>boron (?) </li></ul><ul><li>silica (?) </li></ul><ul><li>essential fatty acids </li></ul><ul><li>Other </li></ul><ul><li>exercise (weight bearing) </li></ul><ul><li>sun exposure </li></ul><ul><li>estrogen (requires proper essential fatty acid intake) </li></ul>03/09/10
  39. 39. Bone Health <ul><li>See which sport enhances bone density in which part of the body </li></ul><ul><li>This is a great site on bone health </li></ul>03/09/10
  40. 40. Sources of Calcium and Vitamin K 03/09/10
  41. 41. Lipid Requirements <ul><li>Which lipids do we need? </li></ul><ul><li>Essential, unsaturated fatty acids </li></ul><ul><li>How much should we get? </li></ul><ul><li>20 -35 % of total calories consumed should be from fats </li></ul><ul><li>Max. 1/3 of total fat calories (=1/10 of total calories) from saturated FAs </li></ul><ul><li>2/3 from unsaturated fats (MUFA and PUFA) </li></ul><ul><li>5 MUFA : 1 PUFA </li></ul><ul><li>4 ω ( omega) 6 : 1 ω 3 </li></ul>03/09/10
  42. 42. Fish Oils and Health For a meat-eating man, replacing 1 meat meal a week with a fish meal reduces his chance of stroke by 20% 03/09/10
  43. 43. Should You Eat Fish Caught in the Waters Around New York City? <ul><li>See next page or click here for Dept. of Health Info </li></ul>03/09/10
  44. 44. Wave of Fish Advisories <ul><li>New figures released by the U.S. EPA show that 35% of lake acreage in the United States and 24% of river miles contain enough pollution to warrant consumption advisories for fish caught in those waters. </li></ul><ul><li>The advisories cover some 40 different substances ; 98% of them involve PCBs, chlordane, dioxins, DDT, or mercury . </li></ul><ul><li>Though the number of advisories rose from 2,814 in 2002 to 3,094 in 2003, EPA administrator Mike Leavitt attributed that increase to more monitoring rather than an increase in pollution. .. 1 </li></ul>03/09/10
  45. 45. 03/09/10
  46. 46. 2003 –Advisories for 86 Water Bodies 03/09/10
  47. 47. Sample Page 03/09/10
  48. 48. Sad - The Skinny On The Fish Oil 1 What the Government Recommends for Fish You Catch 03/09/10
  49. 49. Should You Still Eat Fish? 03/09/10
  50. 50. Find Fish that Are Safe to Eat <ul><li>Click here for lists of mercury contents in fish </li></ul><ul><li>The figures on these lists apply to wild salmon. Also, tuna has since been added to the high mercury list. </li></ul><ul><li>The authors of one study on contaminants in farmed salmon conclude that, because of chemical contaminants, farmed salmon should not be eaten more often than 0.25 to 1 times per month, but see next page </li></ul>03/09/10
  51. 51. Mercury in Fish <ul><li>What Women Should Know About Mercury In Fish Avoid If Pregnant </li></ul><ul><li>Shark Swordfish King mackerel Tilefish Tuna steaks Canned tuna Sea bass Gulf Coast Oysters Marlin Halibut Pike Walleye White croaker Largemouth bass </li></ul><ul><li>Data From The 1970s Show High Concentrations (No Recent Data Available) </li></ul><ul><li>Porgy Orange Roughy Snapper Lake Trout Bluefish Bonito Rockfish </li></ul><ul><li>Eat No More Than One Serving From This List Per Month </li></ul><ul><li>Mahi mahi Blue mussel Eastern oyster Cod Pollock Great Lakes salmon Gulf Coast blue crab Channel catfish (wild) Lake whitefish </li></ul><ul><li>Lowest In Mercury </li></ul><ul><li>Blue crab (mid-Atlantic) Croaker Fish Sticks Flounder (summer) Haddock Trout (farmed) Salmon (wild Pacific) Shrimp * </li></ul><ul><li>* Shrimp fishing and farming practices have raised serious environmental concerns. ** Farmed catfish have low mercury levels but may contain PCBs in amounts of concern for pregnant women. </li></ul>03/09/10
  52. 52. The Environmental Working Group’s Tuna Calculator <ul><li>Click here to find out how much tuna a week you can safely eat </li></ul>03/09/10
  53. 53. Risk-Benefit Analysis of Eating Farmed Salmon <ul><li>The effects were estimated for the European Economic Area countries (population 387 million). </li></ul><ul><li>Here are the estimates: </li></ul>03/09/10 In a population of 387 million (Europe) Estimated Resulting Change in Deaths per Year Excess cancer mortality due to pollutants in farmed salmon + 210 The number of cancer deaths that could be prevented by the restrictive recommendation on farmed salmon use to 1 meal/month + 40 Lost net health effect (cancer and cardiac deaths combined) of unrestricted salmon consumption - 5200
  54. 54. Yes !!! But … <ul><li>The EPA’s advisories for pregnant and breastfeeding women </li></ul><ul><li>This site has lots of info regarding breast-feeding, go to the reference articles on the bottom </li></ul>03/09/10
  55. 55. ω 3 fatty acids (EPA, DHA) vs. methylmercury (MeHg) contents in fish 03/09/10 avoid
  56. 56. Last Not Least - ??? <ul><li>The major changes in the essential fatty acid composition of the food supply, including increased availability of the omega-6 linoleic acid, may be correlated not only with increased risks of homicide, but also increased risks of suicide and suboptimal social cohesion. </li></ul>03/09/10
  57. 57. Bioaccumulation see also  Ecology <ul><li>Toxic mud: </li></ul><ul><li>The Hudson River, a Superfund Site </li></ul>03/09/10
  58. 58. The End Next => Proteins 03/09/10

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